North Carolina State
University scientists have discovered that a substance produced by tomatoes
repels mosquitoes and other insects more effectively than DEET. Entomology
professors at NC State, Dr. Michael Roe and William Neal Reynolds, showed
that the natural compound found in tomatoes is so effective at repelling
insects that the university patented the substance.

The university has
since licensed the right to produce the substance as an insect repellent
to Insect Biotechnology Inc., a Durham company that specializes in developing
and marketing biochemical insecticides. Funding for the research was provided
in part by the National Science Foundation (NSF), the N.C. Biotechnology
Center, the N.C. Agricultural Research Service, and Insect Biotechnology.
Roe's research was also supported by university overhead receipts.

Roe and Insect Biotechnology
Inc. officials believe the substance, which Insect Biotechnology is calling
IBI-246, has the potential to replace DEET as the active ingredient in
most insect repellents.

DEET (short for N,
N-diethyl-meta-toluamide) is a commonly used, yet controversial, insect
repellent. Scientists have raised concerns about DEET's toxic properties
when used alone and in combination with other chemicals. The use of products
containing DEET have been associated with rashes, swelling and itching,
eye irritation and, less frequently, slurred speech, confusion and seizures.
Products with high concentrations of DEET are considered hazardous to
children particularly, and the EPA no longer allows claims on labels of
products containing DEET that the product is safe for children. Recent
research at Duke University with rats showed that frequent and prolonged
use of DEET caused brain-cell death and behavioral changes in the animals.

Roe said he discovered
the repellent capacity of IBI-246 by accident. "I was listening to
a scientific presentation about protein mimics as a diet pill for the
control of mosquito larvae," Roe said. He realized that the compounds
being discussed were similar to a compound found in wild tomatoes that
Roe and another NC State
entomologist, Dr. George Kennedy, had studied a number of years earlier.

Roe and Kennedy had
studied the compound, which apparently is part of the tomato's natural
defenses against insects, to see if it might be used to control worms
that eat tomatoes. Roe revisited the compound and tested it as a mosquito
repellent.

He found that it not
only repelled mosquitoes, but ticks as well. Bennett said subsequent testing
has shown that the substance also repels fleas, cockroaches, ants and
biting flies, as well as insects that are agricultural pests such as aphids
and thrips. Roe said the compound is already used to make cosmetics.

Bennett added that
the cost of producing IBI-246 is expected to be competitive to the production
cost of DEET.
Bennett said Insect Biotechnology has applied to the EPA for approval
to use IBI-246 as an insect repellent in several products. While it is
impossible to tell how long the approval process will take, Bennett said
he is hopeful IBI-246 will win EPA approval by the end of the year.